The purpose of the project is to study the interactions of gonadotropins and the corpus luteum. The activation of adenyl cyclase in isolated ovarian membranes will be correlated with LH and HCG binding to ovarian membranes. Gonadotropin receptors will be solubilized, purified and characterized chemically, physically and immunologically. Attempts to block the function of the corpus luteum selectively at receptor sites by receptor antibody will be made. The mechanism of gonadotropin inactivation in vitro will also be investigated. The development of a receptor assay for practical use will be continued.